A former Iowa legislative clerk has admitted to writing a threatening letter addressed to a state legislator and opening an envelope containing the letter and white powder on the floor of the House, prompting a halt in debate and a lockdown of the Capitol.

The 28-year-old McRae was a clerk for Rep. Ako Abdul-Samad, of Des Moines, in April 2012 when he wrote the letter, which used racial slurs and included threats against himself and the lawmaker. When he opened the envelope on the House floor, a white powder came into contact with McRae and Abdul-Samad.